css-appearance-non-standard-cssom.html

<!DOCTYPE html>

<button id=button>Test</button>
<script>
const [prop, value] = location.search.slice(1).split('&');
// Deprecation warning should be generated if a non standard appearance value was specified.
button.style.setProperty(prop, value);
</script>

chromium/third_party/blink/web_tests/http/tests/inspector-protocol/resources/css-appearance-non-standard-cssom.html